1. Field of the Invention
The present invention generally relates to 120 V duplex electrical receptacles found in 15A and 20A service.
2. Description of the Related Art
NEC code article 210.70 (A)(1) Exception No. 1 states that in other than kitchens and baths, one of more receptacles controlled by a wall switch shall be permitted in lieu of lighting outlets. This is typically accomplished by first wiring any device box intended to have a switched receptacle during the “rough wiring” phase with three-wire Romex or MC cable. Upon the “finish wiring” phase, the device boxes containing the provisions for switching means are ready to attach to the duplex receptacle.
On any residential, commercial, or spec grade receptacle, small tabs are located on both the hot and neutral terminal sides. A three-wire cable typically consists of a black, red, white, and bare copper ground. On the duplex receptacle, the tab on the hot side is broken off, separating the feeds for the top and bottom receptacles. The black wire is constantly hot, while the red is typically terminated on the wall switch load side. The red and black conductors may be positioned however the electrician desires, switching either the top or bottom receptacle.
Once all the duplex receptacles are installed, e.g. in a bedroom, there is no way for the average person to know which receptacles are switched. Many homes, apartments, condos, hotels, etc., are wired this way to save time in the “finish phase” by not having to hang light fixtures, install recessed light trims, and so forth. Numerous service calls to expensive electricians are placed every year by home buyers who think a room was wired with a dead wall switch, or simply cannot figure out why a receptacle has no power (since some electricians switch the entire duplex receptacle).
What is needed, therefore, is a device and method of easily determining whether a receptacle is switched or not.